Valve seat grinding tool



June 12, 1934.

H. G. WOMMER} 1,963,040

VALVE SEAT GRINDING TOOL Filed Nov. 11, 1933 Patented June 12, 1934 UNITED STATES VALVE SEAT GRINDING TOOL Howard G. Wommer, Millersburg, Pa., assignor to Keystone Reamer & Tool Company, Millersburg, Pa., a corporation of Pennsylvania Application November 1 7 Claims.

This invention relates to valve seat grinding tools and, among other objects, aims to provide a simple, efllcient and accurate tool for grinding the valve seats of automotive engines, irrespective of the hardness of the material of which the seats are formed. The idea is to provide a device of this character which will complete the grinding operation very quickly and easily and, at the same time, do very accurate work. Furl0 thermore, it contemplates the provision of a simple and rugged tool which can be operated by any mechanic, the only requirement being that he use reasonable care in applying the tool to produce uniform results in a remarkably short time.

Other aims and advantages of the invention will appear in the specification, when considered in connection with the accompanying drawing, wherein:

Fig. 1 is a sectional view of a tool embodying the invention, showing it applied to a conventional type of valve seat;

Fig. 2 is a section taken on the line 22 of Fig. 1; and

Fig. 3 is a section taken on the line 3-3 of Fig. 1.

Referring particularly to the drawing, the tool there shown is of the type which employs a substantially frusto-conical grinding stone l0 adapted to be rotated on a valve seat 11 of an ordinary internal combustion engine. In accordance with the invention, the stone is given a slight tilting motion on its axis as it rotates so that its grinding surface does not contact with the entire face of the valve seat, enabling only a portion of the stone to do its work on the seat and the dust to be cleared where the stone is out of contact with the seat.

In this instance, the stone is guided to rotate about a pilot 12 in the form of a finished rod firmly fitted into the valve stem guide 13. At the upper portion of this pilot is a floating bushing 1% with its opening drilled out of alinement with its outside circumference, as shown in Fig. 1. its lower end is concentric with the pilot (Fig. 3), and its upper end is eccentric with the pilot as clearly indicated in Fig. 2. This bushing is concentrically mounted within a casing 15 constituting a hollow shaft having a reduced lower end 16 providing an arbor for the stone 10, and is rotatable within said casing, ball bearings having outer rings 17 being firmly fitted within the casing and inner rings 18 being firmly mounted on the floating bushing.

The lower ball bearing rests upon a felt packing at the lower end of the casing to prevent grease from escaping through the stone arbor and the two bearings are spaced apart by a spacing sleeve 19 between the outer rings 1'7. Above the outer ring 17 of the upper ball bearing is 1, 1933, Serial No. 697,649

mounted a shouldered annular washer 21 and a pressure sleeve or ring 22 extending to the upper end of the cylindrical section of the casing. On the upper screw threaded end of the casing 15 is mounted a screw threaded cap member 23 having a shoulder 24 bearing against the pressure sleeve 22, the arrangement being such that the two ball bearings are confined in proper spaced relation within the casing. The cap 23 has an extension 25 to which is connected an ordinary universal coupling 26, the upper end of which is adapted to be clinched in and driven by a small electric drill or other source of power (not shown). It will thus be seen that the electric drill or other power driving means imparts rotation through the casing to the stone. The outer rings of the ball bearings rotate with the casing and rotation is slowly imparted through the balls to the inner rings and to the bushing mounted therein. As the floating bushing rotates slowly about the pilot due to friction, tilting or lateral rocking motion is imparted to the casing and to the stone so that only about one-fourth of the circumference of the stone is in contact with the working face of the-valve seat and the other part of the stone is clear of the seat to permit dust to escape and prevent clogging of the working face of the stone. Under actual operating conditions, the bushing rotates about 100 R. P. M. while the stone is rotating 1500 to 2000 R. P. M. Thus, all parts of the working edge of the stone come in contact with the seat and the stone is worn evenly.

To use the tool properly, the valve guide 13 is first preferably cleaned with a wire brush; the pilot is then inserted in the valve guide; all oil and carbon are then wiped off the valve seat; the cylinder or cylinders and port openings in the motor are covered to keep out the dust; the grinding wheel and the casing are then installed on the pilot after rubbing a little thin grease on the pilot with the finger; and the stone is allowed to come to rest on the valve seat. A small electric drill is then connected by an ordinary chuck to the universal joint; and the operator holds one hand on the drill handle and one hand on the body of the drill, lifting the wheel slightly from the valve seat when the drill is started. After the wheel is brought up to its normal speed, he carefully lowers it to the valve seat to start the grinding operation. The wheel does not require any heavy pressure to do its work rapidly and accurately. In fact, it should be lifted from the seat occasionally to permit the dust to escape from between the stone and the seat. To finishthe work, the wheel is allowed to touch the seat very lightly for a few revolutions before it is lifted clear of the seat. It should be lifted from the seat before the drill is stopped. The grinder is then removed from the pilot and the seat is tested for accuracy.

In some cases, it is desirable to use diiferent stones. For example, if new insert ring seats are 6 to'be ground or large amounts of material are to be removed, it is desirable to employ a roughing wheel first and then to follow this by a fine or finishing wheel. For finishing or regrinding old valve seats, the finishing wheel only is necessary. 10 From the foregoing description, it will be seen that the improved grinder is very rugged and extremely simple in its construction. It is especially adapted for grinding and accurately finishing valve seats of automobile or automotive en--' gines whether the same be made of cast iron,

steel, alloy steel, high speed steel, stellite or other hardened metals. In fact, the grinder is adapted for universal valve grinding workand will grind especiallyhardened seats which cannot be finished by the ordinary cutting tools and reamers. It does the work very accurately and quickly and saves considerable expense. There are no partsthat require quick replacement. A good set of stones will last almost indefinitely, if kept 8i properly dressed and free of oil or grease.

' Obviously, the present invention is not' restricted to the particular embodiment thereof herein shown and described. Moreove it is not indispensable that all the features of the inven- 80 tion be used conjointly, since they may be employed advantageously in various combinations and sub-combinations.

What is claimed is: 1. A valve seat grinder of the character de- 85 scribed comprising, in combination, a pilot adapted to be fitted in a valve guide; a casing constituting a shaft having an arbor on its lower end rotatably mounted on said pilot; a grinding stone removably mounted on the arbor; said 40 casing can'ying a floating bushing mounted in ball bearings to be eccentrically mounted at its upper end on said pilot and concentrically mounted at its lower end on. said pilot and adapted to impart eccentric movement to the upper part of the casing; and a universal joint on the upper end of the casing adapted to be driven by a source of power.

2. A valve grinding tool of the character described comprising, in combination, a cylindrical l0 pilot adapted to be mounted concentrically within a valve seat; a casing constituting a shaft carrying a removable stone at its lower end; a fioatingbushing having an eccentrically bored opening to be fitted on'the pilot and arranged $5 to impart eccentric movement to the upper end of the casing and tilting movement to the stone; a pair of spaced anti-friction bearings between the casing and said floating bushing adapted to impart frictional rotation to the floating bush- Q0 ing; a cap for the casing havinga driving extension; and a universal joint on said extension adapted to be connected to a power driven chuck so as to impart rotation to the stone.-

3. A valve seat grinder of the character described comprising, in combination, a pilot adapted to be inserted firmly within the valve stem guide; a substantially cylindrical casing having a reduced extension'at its lower end constituting an arbor; a grinding stone removably mounted 7 on the arbor; a floating bushing within the casing having an eccentric opening closely fitted to the pilot and arranged to impart eccentric movement to the upper end of the casing as it rotates the stone about the pilot; a pair of spaced ball bearings arranged between the casing and said floating bushing; a driving extension on the casing; and a universal joint on the driving extension adapted to be driven by a source of power and permitting slight eccentric movement of the casing as the stone is rotated on the seat.

ed to rotate about the pilot; a stone arbor on the lower end of the casing; a stone removably secured to the stone arbor for dressing a valve seat; afioating bushing within the casing to be concentrically mounted at its lower end on the pilotand eccentrically mounted at its upper end on the pilot; a pair of spaced ball bearings between the casing and the bushing; a spacing sleeve between the bearings; means to clamp the outer ring of the upper ball bearing within the casing against said spacer sleeve; acap member on the casing having a driving extension; and a universal joint on the extension adapted to be connected to a source of power to rotate said grinder.

5. A valve seat grinder of the character described comprising, in combination, a pilot rod accurately finished to fit firmly in a valve stem guide; a casing constituting a driving shaft adapted to rotate about the pilot and having a reduced extension providing a stone carrying arbor on its lower end; a stone removably mounted on said extension; a floating bushing with its opening drilled out of alinement with its outside circumference, arranged within the casing and adapted to be concentrically mounted at its lower end on the pilot and eccentrically mounted at its upper end on the pilot; a ball bearing within the casing at the lower end; a felt washer between the bottom of the casing and said ball bearing; a spacer sleeve within the casing; an upper ball bearing within the casing above the spacer sleeve; a washer on the outer ring of the upper ball bearing; a clamping sleeve in the upper end portion of the casing mounted on said washer; a screw threaded cap connected to the upper end of the casing and having a shoulder exerting clamping pressure on said clamping sleeve; a driving extension on said cap; and a universal joint on said driving extension adapted to be connected to an electric drill to impart rotation to the stone and permit eccentric move- .125 ment of the upper end portion of the casing as the casing rotates about the pilot.

6. A valve seat grinder comprising; in combination, a pilot adapted to' be inserted in a valve stem guide; a hollow shaft carrying a grinding stone on'its lower end; and an eccentric bearing member within the hollow shaft mounted on the pilot and confining the shaft to rotate about an axis at a small angle to the axis of the pilot, whereby rotation of the ,shaft imparts tilting mozement to the stone as it operates on the valve sea 7. In a valve grinder of the character described, a pilot adapted to be inserted in a valve stem guide; a'shaft. carrying a grinding wheel at its lower end and adapted to rotate about the pilot; and an eccentric bearing member cooperating with the shaft and the pilot positioning the shaft with its axis at a small angle to the axis of the pilot, the lower end of the shaft being substantially coaxial with the pilot whereby tilting motion is imparted to the grinding wheel as it operates on the valve seat.

HOWARD G. WOMMER. 

